Can portfolios be constructed entirely of ETFs?

As one of the fastest developing investment industries of the past decade, exchange traded funds (ETFs) are rarely far from the headlines. In the past few years, we have seen impassioned debates on physical versus swap-based ETFs, the merits of active ETFs, dividend-enhanced ETFs, commodity ETFs, bond ETFs, alternative ETFs… So, what's new? Recent figures from Deutsche Bank show some interesting trends. The first of these is that, while the assets managed by ETF providers continue to expand apace, the rate of increase in the number of ETFs (see figure one, below) has come back signifi...